-LRB- CNN -RRB- Protests are gaining steam in Baltimore after a man died from a devastating injury he allegedly suffered while in police custody .

Demonstrators have vowed they 'll keep taking to the streets until they get justice . To start , protesters say they 're looking for answers about what happened to Freddie Gray , and why .

But it seems like the questions in the controversial case just keep growing .

Protesters rallied at Baltimore City Hall on Thursday , and another march is planned for Saturday . Here 's a look at key issues protesters are asking about :

Police say when Gray saw police on April 12 , he started running . Within minutes , they caught up with him and arrested him after finding a knife in his pocket .

Protesters have echoed the claims of the Gray family 's attorney , who argues that police did n't have any probable cause to pursue him , but chased him for `` running while black . ''

Baltimore Police union attorney Michael Davey told reporters Wednesday that officers had every right to chase Gray .

`` There is a Supreme Court case that states that if you are in a high-crime area , and you flee from the police unprovoked , the police have the legal ability to pursue you , and that 's what they did , '' he said . `` In this type of an incident , you do not need probable cause to arrest . You just need a reasonable suspicion to make the stop . ''

An autopsy says Gray died from a severe spinal cord injury . His family says his voice box was crushed and his neck snapped before he slipped into a coma and later died .

Police say they spotted Gray , gave chase , caught him , cuffed him and requested a `` wagon '' to transport him in less than four minutes .

The transport van left with Gray about 11 minutes afterward , police said , and another 30 minutes passed before `` units request paramedics to the Western District to transport the suspect to an area hospital . ''

Protesters want to know exactly what happened in those 30 minutes , and say it 's clear police used too much force when Gray was in their custody .

Investigators still have n't said what happened inside the van .

Union officials from the Fraternal Order of Police Lodge 3 say something happened inside the vehicle , but they do n't know what .

Baltimore Police Commissioner Anthony Batts told CNN affiliate WJZ that another prisoner inside the van said he did n't see any harm done to Gray .

`` What he has said is that he heard Freddie thrashing about , '' Batts said . `` The driver did n't drive erratically , was n't slamming on breaks , was n't turning corners fast or in an irrational way . ''

Five of the six officers involved in Gray 's arrest have provided statements to investigators , the Baltimore Police Department said Wednesday .

`` They have completely cooperated with the investigation from Day 1 , '' Davey told reporters .

But details of what the officers said have n't been released yet by authorities .

Neither have the officers ' personnel records or photos . Police say doing that would violate the law .

The lack of details a week and a half after the incident is fueling cries from the public , and the lawmakers who represent them . Protesters say police should be releasing what they know now .

Baltimore Police officials say they 're being as transparent as they can about the case while their criminal investigation is ongoing . And they say they plan to hand over details from the investigation to the State Attorney 's Office next week .

Some protesters say the officers should be charged with murder for Gray 's death . Officials say an investigation is ongoing , and all the officers involved have been suspended with pay . At this point , it is n't clear whether any charges will be filed .

The U.S. Justice Department is also investigating the case .

The police union said it 's 100 % behind the officers and compared protesters to a lynch mob , accusing them of calling for charges against officers without knowing the facts of the case or giving them a day in court .

`` There is , at this time , no indication of any criminal activity whatsoever , '' the union 's statement said , `` but our support will not waiver for any reason . ''

Gray 's case is getting a lot of attention . But protest organizers say it 's emblematic of a broader problem .

Some protesters say it 's not the only time they 've seen police brutality on the streets of their city .

Long before they took to the streets to demonstrate over Gray 's death , some of them had already been at city hall , voicing their concerns over other cases .

`` Right now there 's a lot of mistrust . They feel it 's us versus them , '' Baltimore City Council President Jack Young said . `` It should not be that way and it needs to be fixed . ''

According to the Baltimore Sun , the city has paid more than $ 5.7 million since 2011 for more than 100 cases involving allegations of police wrongdoing .

Police did n't admit fault in any of the cases . The police union said in a statement on Wednesday that the reason for the settlements was simple : City officials believe lawsuits are too costly .

`` Let us be clear , we completely disagree with this policy , as many of these cases are settled without concern for the facts but , rather , to avoid the high cost of defending a potential lawsuit . We believe that these cases should be decided in court where proper time and attention can be given , '' the union said . `` The ease of settlement , and substantial award amount , has led to the unjustified perception of an increase in brutality complaints . ''

CNN 's Dana Ford , Eliott C. McLaughlin , Suzanne Malveaux , Jake Tapper , Miguel Marquez , Brian Todd , Polo Sandoval , Justin Lear , Jason Carroll and Patrick Cornell contributed to this report .

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Freddie Gray 's death has fueled protests in Baltimore

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Demonstrators accuse police of using too much force and say officers should face charges